This invention relates to the repair of damaged laminated safety glass or shatter-proof glass commonly used in the manufacture of automobile windshields, for example. Because such safety glass comprises a lamination of two plates of glass sandwiching a transparent binder, localized impact damage resulting in so-called "bulls-eye", "half-moon", "daisy" and "star", cracks usually affects only the outer plate of the lamination. For this reason it has been found that such localized cracked zones can be filled with transparent resins while in the liquid state to restore substantially the original transparency, visibility and strength to the windshield. Various systems and apparatus have been devised for carrying out such repairs, all of which have in common a support structure securable in surrounding relation with respect to the damaged glass zone to be repaired, mechanism for applying the repair fluid against the damaged zone within such a supporting structure, and means for effecting a vacuum within the supporting structure to withdraw air from the damaged zone and, in some instances, subsequently applying pressure thereat so as to replace all of the voids created by the damage with a clear polymerizable fluid. U.S. Pat. No. 4,047,863 to McCluskey et. al., 4,165,397 to Ogden et. al. and 4,200,478 to Jacino et. al. describe such damaged shatter-proof or safety glass repair apparatus. In each instance of the prior art apparatus, the repair fluid is placed and contained against the outside of the damaged zone in such a way as to obstruct any possibility of mechanically stressing the damaged zone by manipulation of a tool from the outside of the vacuum containing apparatus and while the damaged zone is under air pressure. Such mechanical stressing at the damaged zone while under air pressure and flooded with the repair fluid has been found to greatly facilitate the rapidity and completeness with which the fluid replaces air in all multiple fissures and interstices of the damaged zone.
It is, accordingly, the principal object of this invention to provide a novel and improved apparatus for repairing laminated or safety glass that permits mechanically stressing the damaged glass zone while under either vacuum or pressure and while flooded with the repair fluid.
It is another object of the invention to provide a repair apparatus of the character described wherein the repair fluid is applied by injection through a resilient disk into the vacuum or pressurized area surrounding the damaged zone, the tip of the hollow needle or cannula of the medical syringe serving as a tool for applying mechanical pressure to the damaged zone by manipulation of the syringe from the outside.
It is yet another object to provide a repair apparatus of the above nature in which the amount of repair fluid deposited can be closely controlled during the repair process by use of the syringe.
Still another object is to provide a repair apparatus of the character described wherein the air pressure and vacuum supplied above the damaged glass area are supplied through flexible hoses leading to the vacuum and/or pressure pumps for remote control, whereby the operator can perform the repair procedure of the most part at a convenient location, such as within the vehicle rather than at the outside. This is especially important in inclement weather and instances where the damage to be repaired is inconveniently located, such as high on the windshield of a large bus or truck.
Yet another object of the invention is to provide a repair apparatus of the character described wherein contact of the repair fluid with the fluid retaining means surrounding the damaged zone is kept to a minimum to facilitate clean-up upon completion of the procedure, and wherein repair time and labor is kept to a minimum by use of inexpensive, disposable medical syringes.
Yet another object of the invention is to provide a laminated safety glass repair apparatus of the character described which will be inexpensive to manufacture, superior in performance, and simple and long-wearing operation.
Other objects, features and advantages of the invention will be apparent from the following description when read with reference to accompanying drawings.